Effect of SiO2 additive on the mechanical and dielectric properties of PZFNTU ceramics

Composite of Pb(Zr0.58Fe0.20Nb0.20Ti0.02)(0.994)U0.006O3 (PZFNTU) ceramics with SiO2 additive has been prepared by the conventional powder processing method. Microhardness, flexural strength, and the dielectric properties of the sintered material have been studied. It is found that a small amount of SiO2 improves the flexural strength, the microhardness and the dielectric constant of the sintered PZFNTU ceramics. It is also found that the fracture mode changes from intergranular to essentially transgranular with the small amount of SiO2. For large amount of SiO2 additives, the sintered ceramics are more porous and the strength and hardness values are also low. For ceramics with small amount of SiO2 additives, the structure is purely perovskite while for large amount of SiO2 additives, pyrochlore phases are detected.